Automatic control production method for chlorine introduction reaction of chlorinated polyethylene

Abstract

The invention relates to the technical field of chlorinated polyethylene production, and discloses a chlorinated polyethylene chlorine introduction reaction automatic control production method, which comprises the following steps: by using 17% hydrochloric acid as a suspension medium, putting the 17% hydrochloric acid into a reaction kettle, adding an auxiliary agent into an acid phase to suspend high density polyethylene powder in the acid phase, introducing steam into a jacket of the reaction kettle, and reacting for 2-3 hours; raising the temperature of the material, and starting to introduce chlorine to carry out substitution reaction when the temperature reaches the process temperature; in the reaction process, heat is released continuously; and removing acidic substances from the material after the reaction is finished, feeding the material after deacidification and alkali neutralization into a continuous discharging boiling fluidized drying bed for drying, and obtaining the chlorinated polyethylene resin after drying. According to the chlorinated polyethylene chlorine introduction reaction automatic control production method, the labor intensity of operators is reduced, and the defects that in the chlorinated polyethylene production process, the automation degree is not high, manual operation is mainly adopted in a production field, labor consumption is large, and operation is unstable are overcome.

Description

Technical Field

[0001] This invention relates to the field of chlorinated polyethylene production technology, specifically to an automated control method for the chlorination reaction of chlorinated polyethylene. Background Technology

[0002] Chlorinated polyethylene (CPE) is a novel saturated polymer material, appearing as a white powder. It is non-toxic and odorless, possessing excellent weather resistance, ozone resistance, chemical resistance, and aging resistance. It also exhibits good oil resistance, flame retardancy, and colorability. It has good toughness (remaining flexible at -30℃), good compatibility with other polymer materials, and a relatively high decomposition temperature. It is widely used in PVC pipes, profiles, sheets, flame-retardant cable sheaths, and various sealing strips.

[0003] Traditional production relies on manual control, requiring calculations and operations simultaneously according to process requirements. This is time-consuming, mentally taxing, and difficult to control. One person can only monitor a maximum of one reactor at a time, and the process is highly unstable, prone to large errors, and results in inconsistent product quality. Therefore, a corresponding technical solution needs to be designed to address this issue. Summary of the Invention

[0004] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides an automated control method for the chlorination reaction of chlorinated polyethylene. This method solves the technical problems of manual control, which requires calculation and operation according to process requirements, is time-consuming and mentally taxing, difficult to control, and only allows one person to monitor one reactor at a time. Furthermore, it is unstable, has large errors, and results in inconsistent product quality.

[0005] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: an automated control method for the chlorination reaction of chlorinated polyethylene, comprising the following steps: S1. Ingredient preparation: According to the process instruction sheet, PE raw materials are transported to the high-level weighing silo by a fresh air conveying system for later use. The prepared 17% hydrochloric acid is automatically pumped to the batching vessel under the control of DCS. The specified additives are added, and a certain amount of PE raw materials are automatically added to suspend the high-density polyethylene powder in the 17% acid phase. The stirring is turned on, the control system is started with one button, the temperature is automatically raised to 70℃, and the conveying pump is automatically turned on to transfer the prepared slurry to the corresponding chlorination reactor. S2. Reaction process: Steam is introduced into the jacket of the reactor to heat the material until the process temperature is reached. Once the process temperature is reached, chlorine gas is introduced to carry out the substitution reaction. During the reaction, heat is continuously released, and a certain amount of cooling water needs to be continuously injected into the jacket of the reactor to control the rate of temperature rise. Once the required chlorine content for the process is met, the chlorine supply is cut off, and chlorinated polyethylene is produced. S3. By-product treatment: The hydrogen chloride produced during the reaction dissolves in the hydrochloric acid phase to form 25% high-concentration hydrochloric acid. Part of the high-concentration hydrochloric acid is recycled for use, and part is sold as a by-product. S4. Post-processing: After the reaction is completed, the material is centrifuged to remove high concentrations of hydrochloric acid from the mother liquor. The separated material is diluted with process water and then transferred to a transfer soaking tank. S5. The centrifuge removes some of the internal acid, and the dilute acid in the centrifuged mother liquor is recycled. After centrifugation, the material is mixed with the finished centrifugal mother liquor (water), and the slurry is fed into a neutralization kettle. Alkali is added and the temperature is raised to make the particles expand, which facilitates the release of acid and achieves neutralization. The PID module controls the acidity and alkalinity through a pH meter. The neutralization vessel is equipped with a pH meter, temperature probe, alkali addition regulating valve, steam regulating valve, etc., to realize automatic alkali addition and one-button start-up for heating. S6. After the material is neutralized and qualified, it is conveyed to a fully automatic belt centrifuge by a conveying pump to separate the mother liquor and remove excess alkali salts. Process water is then added, and the material enters the slurry tank, which is equipped with a level gauge and a temperature sensor. The process is equipped with flow meters and pneumatic regulating valves, and the entire process is automatically controlled and started with one button according to process parameters; S7. The material entering the slurry tank is pumped to a centrifuge for dehydration and then enters a continuous discharge fluidized bed dryer for drying. After drying, chlorinated polyethylene resin is obtained.

[0006] Preferably, a DCS distributed control system is used as the top-level architecture, and a dedicated PID control module is integrated to achieve precise automated control. The control system is divided into a chlorination process instruction module, a one-button start module, a temperature control module, a steam heating module, a cooling module, a temperature deviation module, a cooling water temperature and flow rate regulation module, a liquid chlorine flow rate accumulation module, a liquid chlorine flow rate regulation module, a cooling water return module, a steam condensate module, a circulating hot water module, and a circulating cooling water module.

[0007] Preferably, the additives include dispersants and emulsifiers. Dispersant: During the reaction of chlorinated polyethylene, side reactions and adhesion are prone to occur. Dispersants are used to reduce the occurrence of side reactions and particle adhesion. Emulsifiers include fatty alcohol polyoxyethylene ethers and polyvinylpyrrolidone.

[0008] Preferably, in step S2, the specific method for introducing chlorine gas to carry out the substitution reaction includes the following steps: S201, after reaching the process temperature, chlorine gas is introduced to carry out the substitution reaction. The chlorine gas is introduced through liquid chlorine pipeline distribution nozzles to ensure that the chlorine gas is evenly distributed in the reaction system. S202 continuously releases heat during the reaction process. The rate of temperature rise is controlled by injecting cooling water of different temperatures into the jacket, and the temperature is controlled by adjusting the flow rate of water entering and leaving the jacket. S203, according to process requirements, maintain an appropriate reaction time to ensure that the reaction reaches the expected extent; S204: Once the required chlorine content for the process is met, the chlorine supply is cut off, and the substitution reaction ends.

[0009] Preferably, the substitution reaction of chlorinated polyethylene is represented by the following reaction equation: (CH2=CH2)n+nCl2→(CH2-CHCl-)n; In this context, (CH2=CH2)n represents the starting material for polyethylene, n is the degree of polymerization, Cl2 represents chlorine gas, and (CH2-CHCl-)n represents the chlorinated polyethylene produced.

[0010] Preferably, in step S4, the specific method for deacidifying and filtering the material after the reaction is completed is as follows: S401, Prepare the filtration equipment: The DCS prepares each transfer device to the pre-start state, clears the cumulative flow of each flow meter to zero, sets the transfer material flow rate and the flushing water flow rate, and prepares sufficient clean water and spray devices. S402, Transferring Materials: Transferring the materials after the reaction is complete from the reactor to a centrifuge using a slurry pump; S403, Start the centrifuge: Transfer the material into the drum of the fully automatic belt centrifuge, automatically control the set flow rate to ensure that the material enters the centrifuge evenly; use the centrifugal force of the equipment to separate the mother liquor and remove high concentrations of hydrochloric acid; S404, the filtered material is a powder with a water content of 10%. The material is turned into a slurry through an automatic water addition system and enters the transfer soaking tank. Stirring is started to dilute the acid inside the material. S405, the material then passes through a deacidification centrifuge to remove some of the internal acid: the DCS sets the centrifuge feed rate and controls the centrifugation speed. The feed rate is interlocked with the centrifuge motor current to ensure that the material moisture content is around 10%. S406, the dilute acid discharged from the deacidification centrifuge is precipitated and filtered, and then mixed with concentrated acid for feeding and recycling.

[0011] Preferably, in step S4, the deacidified material is added to the finished centrifugal mother liquor, and then neutralized with alkali in a neutralization kettle to neutralize the internal acid and make the material neutral before entering the continuous discharge sulfidation drying bed. The steps for neutralization are as follows: S501. After deacidification and centrifugation, the material is added to the finished centrifugal mother liquor and then pumped to the neutralization vessel. The centrifuge feed rate and the amount of finished centrifugal mother liquor added are both equipped with flow meters. The neutralization vessel is equipped with a pH meter, temperature sensor, level gauge, liquid alkali regulating valve and steam heating regulating valve. The alkali addition and neutralization process is controlled by a PLC module to achieve one-button start. S502, after neutralization and qualification, the material is conveyed by a conveyor pump to a belt filter for mother liquor separation, removing excess alkali and salt adsorbed on the surface; S503. After filtration, the mother liquor is filtered through a settling tank and sent to the treatment plant. Process water is added to the material and added to the mixing slurry tank before entering the next process. The drying method and steps are as follows: S601. Prepare the centrifugal drying equipment: Ensure that the continuous discharge fluidized bed is in normal working condition. Set the parameters such as air inlet temperature, air inlet volume, and negative pressure of each compartment of the drying bed according to the process instruction sheet. Check its operation status to ensure that the drying bed can operate normally. S602. Transferring materials: Start the conveying pump and centrifuge, and transfer the centrifuged material to the continuous discharge fluidized bed dryer via a rotary conveyor. S603. Start the drying equipment: Next, start the control system and heating system of the fluidized bed through the DCS; according to the preset process requirements, automatically control the air inlet temperature and air volume of each compartment of the fluidized bed. S604. Drying process: At the set temperature, heat is transferred to the material through heating equipment; during this process, the material gradually loses moisture and dries; to ensure the drying effect, the temperature of each compartment is interlocked with the steam regulating valve, and the moisture content of the material is also interlocked with the centrifuge feed rate, so as to achieve automatic adjustment and no on-site operators are required; S605. Drying and Discharging: When the material reaches the predetermined value, the material enters the drying and cooling bed through the automatic star-shaped discharge valve and is cooled to 40℃. After passing the temperature test, the material enters the air conveying system through the star-shaped discharge valve with the flow rate automatically controlled. S606, Mixing and Packaging: The material is pneumatically conveyed to the dust collector and fed into the weighing mixer. According to industry standards, the dried material is further mixed. The system automatically adds a release agent according to the set ratio based on the material weight and the PLC automatic control module. Then it enters the fully automatic packaging system and is packaged into 25kg packages for warehousing.

[0012] Preferably, the control system includes a liquid chlorine flow meter, a chlorine regulating valve, a liquid chlorine shut-off valve, a steam regulating valve, a cooling water flow meter, a primary water regulating valve, a hot water regulating valve, a steam condensate outlet shut-off valve, and a cooling return water shut-off valve throughout the entire batching and chlorination process.

[0013] (III) Beneficial Effects Compared with the prior art, the beneficial effects of the present invention are: after the chlorination reaction is automated, not only is the labor intensity of the operators reduced, but also the instability of the chlorination reaction process caused by human operation is reduced, which leads to the instability of product quality indicators. After automating the chlorination reaction, the program automatically controls the temperature difference between the jacket and the inside of the reactor, ensuring that it does not exceed the upper limit of the allowable temperature difference of the reactor, thereby protecting the enamel of the reactor and extending the service life of the reactor. This technology addresses the shortcomings of previous chlorinated polyethylene production processes, such as low automation, reliance on manual operation, high labor costs, and unstable operation. It also enables comprehensive monitoring of key personnel in production workshops (areas) involving nitration, hydrogenation, chlorination, fluorination, diazotization, and peroxidation processes with a hazard level of 3 or higher, as well as in positions such as deacidification, drying, pneumatic conveying, and mixing and packaging. Through years of experience and by combining modern DCS / PID control technology, a one-button start technology for fully automated control of the entire chlorinated polyethylene production process has been successfully developed. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the process flow of the present invention; Figure 2 This is a schematic diagram of the ingredient dispensing unit of the present invention; Figure 3 This is a schematic diagram of the chlorination unit of the present invention; Figure 4 This is a schematic diagram of the cooling and material waiting unit of the present invention; Figure 5 This is a schematic diagram of the deacidification filtration unit of the present invention; Figure 6 This is a schematic diagram of the transfer vessel unit of the present invention; Figure 7 This is a schematic diagram of the deacidification centrifugation unit of the present invention; Figure 8 This is a schematic diagram of the alkali neutralization unit of the present invention; Figure 9 This is a schematic diagram of the dealkali and desalination filtration unit of the present invention; Figure 10 This is a schematic diagram of the post-processing unit (slurry mixing, finished product centrifugation) of the present invention; Figure 11 This is a schematic diagram of the fluidized drying unit of the present invention; Figure 12 This is a schematic diagram of the pneumatic mixing and packaging unit of the present invention; Figure 13 This is a schematic diagram of the acid preparation method of the present invention; Figure 14 This is a schematic diagram of the raw material feeding, metering, and batching process of the present invention; Figure 15This is a schematic diagram of the material preparation process for the present invention; Figure 16 This is a schematic diagram of the process of removing concentrated acid according to the present invention; Figure 17 This is a schematic diagram of dilute acid centrifugation according to the present invention. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] Please see Figures 1-17 This invention provides a technical solution: an automated control method for the chlorination reaction of chlorinated polyethylene, the method comprising the following steps: S1. Preparation: In the enamel-lined reactor, the acid phase suspension method is used with 17% hydrochloric acid as the suspension medium. 17% hydrochloric acid is added to the reactor, and additives are added to the acid phase to suspend the high-density polyethylene (PE) powder in the acid phase. The overall process control system is started to control the opening and closing of the overall valves. S2. Reaction process: Steam is introduced into the jacket of the reactor to heat the material until the process temperature is reached. Once the process temperature is reached, chlorine gas is introduced to carry out the substitution reaction. During the reaction, heat is continuously released, requiring the continuous injection of cooling water into the reactor jacket to control the rate of temperature rise. Once the required chlorine content for the process is met, the chlorine supply is cut off, and chlorinated polyethylene is produced. S3. By-product treatment: The hydrogen chloride produced during the reaction dissolves in the hydrochloric acid phase to form 25% high-concentration hydrochloric acid. Part of the high-concentration hydrochloric acid is recycled for use, and part is sold as a by-product. S4. Post-processing: After the reaction is completed, the material is centrifuged to remove acidic substances. The material after deacidification and centrifugation is then dried in a continuous discharge fluidized bed to obtain chlorinated polyethylene resin.

[0017] Further improvements include adopting a DCS distributed control system as the top-level architecture and integrating a dedicated PID control module to achieve precise automated control. The control system is divided into a one-button start module, a process instruction sheet module, a temperature control module, a steam heating module, a cooling module, a temperature deviation module, a cooling water temperature and flow rate regulation module, a liquid chlorine instantaneous flow rate accumulation module, a cooling water return module, a steam condensate module, a circulating hot water module, and a circulating cooling water module.

[0018] The one-button start module is used to start and stop the overall process; the process instruction sheet module is used to control the chlorination reaction zone setting value; the temperature control module monitors and controls the setting and adjustment of the reaction temperature; the steam heating module controls the flow rate and temperature of steam entering the reactor jacket to achieve material heating; the cooling module controls the flow rate and temperature of cooling water entering the reactor jacket to achieve material cooling; the temperature deviation module detects the deviation between the reaction temperature and the set temperature and makes adjustments; the cooling water temperature and flow rate adjustment module monitors and adjusts the temperature and flow rate of cooling water to control the rate of reaction temperature rise; the liquid chlorine instantaneous flow rate accumulation module monitors and records the chlorine flow rate entering the reactor; the cooling water return module controls the return flow of cooling water to achieve cooling of the reactor jacket; and the steam condensate module treats the steam condensate generated during the reaction process.

[0019] Further improvements include additives such as dispersants and emulsifiers. Dispersants are used to disperse and isolate substances that are prone to side reactions and adhesion during the reaction of chlorinated polyethylene, thus facilitating the reaction. Dispersants include silica. Composite additives are used to penetrate the chlorinated polyethylene, allowing chloride ions to penetrate to the particle center, thereby increasing the reaction rate and effect, and reducing the crystallinity of the product. Emulsifiers include fatty alcohol polyoxyethylene ether and polyvinylpyrrolidone. In a further improved manner, the specific method for introducing chlorine gas to carry out the substitution reaction in step S2 includes the following steps: S201, after reaching the process temperature, chlorine gas is introduced to carry out the substitution reaction. The chlorine gas is introduced through the liquid chlorine feed pipe and the distribution nozzles to ensure that the chlorine gas is evenly distributed in the reaction system. S202 continuously releases heat during the reaction process. The rate of temperature rise is controlled by injecting cooling water into the jacket, which is achieved by adjusting the flow rate and temperature of the water entering and leaving the jacket. S203, according to process requirements, maintain an appropriate reaction time to ensure that the reaction reaches the expected extent; S204: Once the required chlorine content for the process is met, the chlorine supply is cut off, and the substitution reaction ends.

[0020] Furthermore, the substitution reaction of chlorinated polypropylene is represented by the following reaction equation: (CH2=CH2)n+nCl2→(CH2-CHCl-)n; Wherein, (CH2=CH2)n represents the starting material of polyethylene, n is the degree of polymerization, Cl2 represents chlorine gas, and (CH2-CHCl-)n represents the chlorinated polypropylene produced.

[0021] In a further improvement, the specific steps for filtering the material after the reaction in step S4 are as follows: S401, Prepare the filtration equipment: The DCS prepares each transfer device in the pre-start state, clears the cumulative flow of each flow meter to zero, sets the transfer material flow rate and flushing water volume, and prepares sufficient clean water and washing equipment. S402, Transferring materials: Transferring the materials after the reaction is completed from the reactor to a centrifuge using a slurry transfer pump; S403, Start Centrifugation: One-button start of centrifugation equipment, transfers material to fully automatic belt centrifuge, automatically controls the set flow rate, so that the material enters the centrifugation equipment evenly, and uses the centrifugal force of the equipment to separate the slurry from the mother liquor and remove high concentration hydrochloric acid (25%). S404, the filtered material is a powder with a water content of 10%. The material is turned into a slurry through an automatic water addition system and enters the transfer soaking tank. Stirring is started to dilute the acid inside the material. S405, the material loses some of its internal acid in the deacidification centrifuge: the DCS sets the centrifuge feed rate and controls the filtration speed to ensure that the material moisture content is around 10%; S406, the dilute acid discharged from the deacidification centrifuge, after precipitation, is mixed with concentrated acid for feeding and recycling.

[0022] S407, alkali addition neutralization; after deacidification, the material and process water enter the neutralization kettle. The neutralization kettle is equipped with a pH meter, temperature sensor, level gauge, liquid alkali regulating valve and steam heating regulating valve. The alkali addition neutralization process is controlled by a PID module to achieve one-button start. In a further improvement, the method for drying the neutralized material in step S4, which involves feeding it into a continuous discharge fluidized bed dryer, is as follows: Prepare the drying equipment: Ensure that the continuous discharge fluidized bed dryer is in normal working condition. Set the DCS according to the process instruction sheet to set the parameters such as air inlet temperature, air inlet volume, and negative pressure of each compartment of the dryer. Check its operation status to ensure that the dryer can operate normally. Material transfer: The deacidified material is transferred to a continuous discharge fluidized bed dryer via a screw conveyor. Filled drying bed: The material is uniformly fed into the continuous discharge fluidized bed to ensure that the material layer is uniform and not too dense. The feed rate is automatically adjusted according to the set process parameters to determine the appropriate material filling amount. Start the drying equipment: Start the control system and heating equipment of the continuous discharge fluidized bed dryer, and set the appropriate drying temperature and time according to the process requirements; Drying process: At a set temperature, heat is transferred to the material through heating equipment to gradually remove moisture and dry it. During this process, attention should be paid to controlling the temperature and air volume in the drying bed to ensure the effectiveness of the drying process and the quality of the material. Monitor the drying process: Closely monitor the temperature and air volume during the drying process and make adjustments as needed to ensure the control and stability of the drying process; Drying is completed: When the material reaches the required degree of dryness, it enters the cooling bed and the material temperature drops to 40℃. The drying process is a continuous feeding and discharging process, which realizes automated control. No operators are required on site. The whole process is automatically controlled by DCS, which improves drying efficiency and reduces electricity and steam consumption costs. Remove the dried material: After the material has cooled down, it is continuously discharged into the nitrogen pneumatic conveying system; Subsequent processing: The material is conveyed to the mixer via a pneumatic conveying system. As needed, a certain amount of release agent is added to the dried material for mixing. The mixture then enters the automatic packaging system, and each bag contains 25kg before being stored in the warehouse; ultimately meeting the customer's needs.

[0023] Specifically, the control system includes a chlorine regulating valve, a liquid chlorine flow meter, a cooling water flow meter, a cooling water thermometer, a steam regulating valve, a primary water regulating valve, a hot water regulating valve, a steam condensate outlet shut-off valve, and a cooling return water shut-off valve throughout the chlorination process.

[0024] After one-button start, one person can now operate 10 chlorination reactors and multiple devices at the same time, whereas previously one person could only operate one chlorination reactor and one device at the same time. Each process is very precise. As long as monitoring and inspection are carried out, it saves time and effort and improves product quality. The entire reaction process is divided into three stages: low temperature stage (stage 1), medium temperature stage (stage 2), and high temperature stage (stage 3). The control system is divided into a one-button start module, a process instruction sheet module, a temperature control module, a steam heating module, a cooling module, a temperature deviation module, a cooling water temperature and flow rate regulation module, a liquid chlorine flow rate accumulation module, a cooling water return module, a steam condensate module, a circulating hot water module, and a circulating cooling water module. Combining the three stages of the chlorination reaction, each segment is precisely calculated and controlled based on the control data from different modules, achieving automatic control of the chlorination reaction process. Operators set the process parameters according to the instruction sheet. After starting the chlorination reaction, the reactor automatically heats up. Once the initial chlorination temperature is reached, the chlorination process automatically begins. Throughout the chlorination process, the program automatically controls the reactor's chlorination regulating valve, steam regulating valve, cold water regulating valve, hot water regulating valve, steam condensate outlet shut-off valve, and cooling water return shut-off valve, thereby achieving chlorine flow rate control and reactor temperature control.

[0025] After the production of chlorinated polyethylene is automated, not only is the labor intensity of operators reduced, but the instability of the chlorination reaction process caused by human operation is also reduced, thus reducing the instability of product quality indicators.

[0026] After automating the chlorination reaction, the program automatically controls the temperature difference between the jacket and the inside of the reactor, ensuring that it does not exceed the upper limit of the allowable temperature difference, thereby protecting the reactor enamel and extending the service life of the reactor.

[0027] In order to comply with the relevant requirements of national laws and regulations such as the requirement that no more than 3 people should be on site at the same time, the batching and chlorination processes should be carried out in accordance with the requirements of the "Guidelines for Safety Risk Prevention and Control of Hazardous Chemical Production Construction Projects (Trial)" (Emergency

[2022] No. 52) issued by the Ministry of Emergency Management, the National Development and Reform Commission, the Ministry of Industry and Information Technology, and the State Administration for Market Regulation. 6.2.2 Review Points (9) The upstream and downstream supporting equipment of the nitration, chlorination, fluorination, diazotization and peroxidation process units must realize full-process automated control and mechanized production to minimize the number of on-site personnel.

[0028] This technology effectively addresses the shortcomings of previous chlorinated polyethylene production processes, such as low automation, reliance on manual operation, high labor costs, and unstable operation. It also meets the needs of key monitoring positions in production workshops (areas) involving nitration, hydrogenation, chlorination, fluorination, diazotization, and peroxidation processes with a hazard level of 3 or higher, as well as in deacidification, drying, pneumatic conveying, mixing, and packaging. Through years of experience and the integration of modern PID control technology, a one-button start-up technology for the entire chlorinated polyethylene production process has been successfully developed.

[0029] The process system includes a batching unit, a chlorination unit, a cooling and waiting unit, a post-treatment unit (deacidification and neutralization), a drying unit, and a packaging unit.

[0030] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0031] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An automated control method for the chlorination reaction of chlorinated polyethylene, characterized in that, The method and steps include the following: S1. Ingredient preparation: According to the process instruction sheet, PE raw materials are transported to the high-level weighing silo by a fresh air conveying system for later use. The prepared 17% hydrochloric acid is automatically pumped to the batching vessel under the control of DCS. The specified additives are added, and a certain amount of PE raw materials are automatically added to suspend the high-density polyethylene powder in the 17% acid phase. The stirring is turned on, the control system is started with one button, the temperature is automatically raised to 70℃, and the conveying pump is automatically turned on to transfer the prepared slurry to the corresponding chlorination reactor. S2. Reaction process: Steam is introduced into the jacket of the reactor to heat the material until the process temperature is reached. Once the process temperature is reached, chlorine gas is introduced to carry out the substitution reaction. During the reaction, heat is continuously released, and a certain amount of cooling water needs to be continuously injected into the jacket of the reactor to control the rate of temperature rise. Once the required chlorine content for the process is met, the chlorine supply is cut off, and chlorinated polyethylene is produced. S3. By-product treatment: The hydrogen chloride produced during the reaction dissolves in the hydrochloric acid phase to form 25% high-concentration hydrochloric acid. Part of the high-concentration hydrochloric acid is recycled for use, and part is sold as a by-product. S4. Post-processing: After the reaction is completed, the material is centrifuged to remove high concentrations of hydrochloric acid from the mother liquor. The separated material is diluted with process water and then transferred to a transfer soaking tank. S5. The centrifuge removes some of the internal acid, and the dilute acid in the centrifuged mother liquor is recycled. After centrifugation, the material is mixed with the finished centrifugal mother liquor (water), and the slurry is fed into a neutralization kettle. Alkali is added and the temperature is raised to make the particles expand, which facilitates the release of acid and achieves neutralization. The PID module controls the acidity and alkalinity through a pH meter. The neutralization vessel is equipped with a pH meter, temperature probe, alkali addition regulating valve, steam regulating valve, etc., to realize automatic alkali addition and one-button start-up for heating. S6. After the material is neutralized and qualified, it is conveyed to a fully automatic belt centrifuge by a conveying pump to separate the mother liquor and remove excess alkali salts. Process water is then added, and the material enters the slurry tank, which is equipped with a level gauge and a temperature sensor. The process is equipped with flow meters and pneumatic regulating valves, and the entire process is automatically controlled and started with one button according to process parameters; S7. The material entering the slurry tank is pumped to a centrifuge for dehydration and then enters a continuous discharge fluidized bed dryer for drying. After drying, chlorinated polyethylene resin is obtained.

2. The automated control method for the chlorination reaction of chlorinated polyethylene according to claim 1, characterized in that: The DCS distributed control system is used as the top-level architecture, and a dedicated PID control module is integrated to achieve precise automated control. The control system is divided into a chlorination process instruction module, a one-button start module, a temperature control module, a steam heating module, a cooling module, a temperature deviation module, a cooling water temperature and flow rate regulation module, a liquid chlorine flow rate accumulation module, a liquid chlorine flow rate regulation module, a cooling water return module, a steam condensate module, a circulating hot water module, and a circulating cooling water module.

3. The automated control method for the chlorination reaction of chlorinated polyethylene according to claim 1, characterized in that: Additives include dispersants and emulsifiers. Dispersant: During the reaction of chlorinated polyethylene, side reactions and adhesion are prone to occur. Dispersants are used to reduce the occurrence of side reactions and particle adhesion. Emulsifiers include fatty alcohol polyoxyethylene ethers and polyvinylpyrrolidone.

4. The automated control method for the chlorination reaction of chlorinated polyethylene according to claim 1, characterized in that: In step S2, the specific method for introducing chlorine gas to carry out the substitution reaction includes the following steps: S201, after reaching the process temperature, chlorine gas is introduced to carry out the substitution reaction. The chlorine gas is introduced through liquid chlorine pipeline distribution nozzles to ensure that the chlorine gas is evenly distributed in the reaction system. S202 continuously releases heat during the reaction process. The rate of temperature rise is controlled by injecting cooling water of different temperatures into the jacket, and the temperature is controlled by adjusting the flow rate of water entering and leaving the jacket. S203, according to process requirements, maintain an appropriate reaction time to ensure that the reaction reaches the expected extent; S204: Once the required chlorine content for the process is met, the chlorine supply is cut off, and the substitution reaction ends.

5. The fully automated production method for chlorinated polyethylene chlorination reaction according to claim 4, characterized in that: The substitution reaction of chlorinated polyethylene is represented by the following reaction equation: (CH2=CH2)n+nCl2→(CH2-CHCl-)n; In this context, (CH2=CH2)n represents the starting material for polyethylene, n is the degree of polymerization, Cl2 represents chlorine gas, and (CH2-CHCl-)n represents the chlorinated polyethylene produced.

6. The automated control method for the chlorination reaction of chlorinated polyethylene according to claim 1, characterized in that: In step S4, the specific steps for deacidifying and filtering the material after the reaction are as follows: S401, Prepare the filtration equipment: The DCS prepares each transfer device to the pre-start state, clears the cumulative flow of each flow meter to zero, sets the transfer material flow rate and the flushing water flow rate, and prepares sufficient clean water and spray devices. S402, Transferring Materials: Transferring the materials after the reaction is complete from the reactor to a centrifuge using a slurry pump; S403, Start the centrifuge: Transfer the material into the drum of the fully automatic belt centrifuge, automatically control the set flow rate to ensure that the material enters the centrifuge evenly; use the centrifugal force of the equipment to separate the mother liquor and remove high concentrations of hydrochloric acid; S404, the filtered material is a powder with a water content of 10%. The material is turned into a slurry through an automatic water addition system and enters the transfer soaking tank. Stirring is started to dilute the acid inside the material. S405, the material then passes through a deacidification centrifuge to remove some of the internal acid: the DCS sets the centrifuge feed rate and controls the centrifugation speed. The feed rate is interlocked with the centrifuge motor current to ensure that the material moisture content is around 10%. S406, the dilute acid discharged from the deacidification centrifuge is precipitated and filtered, and then mixed with concentrated acid for feeding and recycling.

7. The automated control method for the chlorination reaction of chlorinated polyethylene according to claim 1, characterized in that: In step S4, the deacidified material is added to the finished centrifugal mother liquor, and then neutralized with alkali in a neutralization kettle to neutralize the internal acid and make the material neutral before it enters the continuous discharge sulfidation drying bed. The steps for neutralization are as follows: S501. After deacidification and centrifugation, the material is added to the finished centrifugal mother liquor and then pumped to the neutralization vessel. The centrifuge feed rate and the amount of finished centrifugal mother liquor added are both equipped with flow meters. The neutralization vessel is equipped with a pH meter, temperature sensor, level gauge, liquid alkali regulating valve and steam heating regulating valve. The alkali addition and neutralization process is controlled by a PLC module to achieve one-button start. S502, after neutralization and qualification, the material is conveyed by a conveyor pump to a belt filter for mother liquor separation, removing excess alkali and salt adsorbed on the surface; S503. After filtration, the mother liquor is filtered through a settling tank and sent to the treatment plant. Process water is added to the material and added to the mixing slurry tank before entering the next process. The drying method and steps are as follows: S601. Prepare the centrifugal drying equipment: Ensure that the continuous discharge fluidized bed is in normal working condition. Set the parameters such as air inlet temperature, air inlet volume, and negative pressure of each compartment of the drying bed according to the process instruction sheet. Check its operation status to ensure that the drying bed can operate normally. S602. Transferring materials: Start the conveying pump and centrifuge, and transfer the centrifuged material to the continuous discharge fluidized bed dryer via a rotary conveyor. S603. Start the drying equipment: Next, start the control system and heating system of the fluidized bed through the DCS; according to the preset process requirements, automatically control the air inlet temperature and air volume of each compartment of the fluidized bed. S604. Drying process: At the set temperature, heat is transferred to the material through heating equipment; during this process, the material gradually loses moisture and dries; to ensure the drying effect, the temperature of each compartment is interlocked with the steam regulating valve, and the moisture content of the material is also interlocked with the centrifuge feed rate, so as to achieve automatic adjustment and no on-site operators are required; S605. Drying and Discharging: When the material reaches the predetermined value, the material enters the drying and cooling bed through the automatic star-shaped discharge valve and is cooled to 40℃. After passing the temperature test, the material enters the air conveying system through the star-shaped discharge valve with the flow rate automatically controlled. S606, Mixing and Packaging: The material is pneumatically conveyed to the dust collector and fed into the weighing mixer. According to industry standards, the dried material is further mixed. The system automatically adds a release agent according to the set ratio based on the material weight and the PLC automatic control module. Then it enters the fully automatic packaging system and is packaged into 25kg packages for warehousing.

8. The automated control method for the chlorination reaction of chlorinated polyethylene according to claim 1, characterized in that: Throughout the entire batching and chlorination process, the control system includes a liquid chlorine flow meter, a chlorine regulating valve, a liquid chlorine shut-off valve, a steam regulating valve, a cooling water flow meter, a primary water regulating valve, a hot water regulating valve, a steam condensate outlet shut-off valve, and a cooling return water shut-off valve.

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